1. Field of the Invention
The present invention relates to a four-wheeled utility vehicle suitable for carrying goods in outdoor spaces or in wide indoor spaces and provided with a cabin frame (also called as a cab frame) surrounding an operators seat.
2. Description of the Related Art
Referring to FIGS. 8A and 8B showing a general four-wheeled utility vehicle disclosed in Japanese utility model Publication No. Shou 63-202579, the four-wheeled utility vehicle has a body frame 10 of a metal, four wheels, i.e., two front wheels 2 and two rear wheels 3, suspended from the body frame 10, a driving unit, such as an engine, mounted on the body frame 10, a driver""s seat 4 and a load-carrying platform 5. The four-wheeled utility vehicle is often provided with wide tires suitable for traveling on rough roads.
A cabin frame 20xe2x80x2 is disposed in front of the load-carrying platform 5 so as to cover the front, rear, right and left sides of the driver""s seat 4. The cabin frame 20xe2x80x2 protects the driver. A roof or a hood, not shown, can be attached to the cabin frame 20xe2x80x2 to screen the driver""s seat 4 from rain and sunshine, and lighting devices 7 can be attached to the cabin frame 20xe2x80x2 for illumination to facilitate work at night.
As shown in FIGS. 8A and 8B, a front portion of the cabin frame 20xe2x80x2 has a rectangular frame having front pillars 21xe2x80x2 and a cross bar 21hxe2x80x2 extended between the front pillars 21xe2x80x2. Lower end portions of the front pillars 21xe2x80x2 of the cabin frame 20xe2x80x2 are held on a front part of the body frame 10 by joints 23xe2x80x2. The joints 23xe2x80x2 have substantially horizontal joining surfaces that are fastened to front right and front left portions of the body frame 10 with bolts having their axes substantially vertical.
This known four-wheeled utility vehicle has the following problems.
a) The interval between the right and left joints 23xe2x80x2 holding the lower end portions of the front pillars 21xe2x80x2 xe2x80x2must be accurately determined so that the right and left joints 23xe2x80x2 coincide with joining portions of the boy frame 10, respectively. Holes, not shown, for passing the bolts must be formed in the right and left joints 23xe2x80x2 at an interval accurately corresponding to an interval between holes for bolts on the body frame 10. If the interval between the holes formed in the body frame 10 (distance p in FIG. 8A) and the interval between the holes formed in the joints 23xe2x80x2 holding the lower end portions of the front pillars 21xe2x80x2 of the cabin frame 20xe2x80x2 are different, the bolts cans be passed through the holes toned in the joints 23xe2x80x2 and the corresponding holes formed in the body frame 10. As a result, the joints 23xe2x80x2 cannot be fastened to the body frame 10. When the cross bat 21hxe2x80x2 is extended between the lower end portions of the front pillars 21xe2x80x2 of the cabin frame 20xe2x80x2 as shown in FIG. 8a to increase the rigidity of the cabin frame 20xe2x80x2 and the holes of the joints 23xe2x80x2 and the holes of the body frame 10 do not coincide with each other, additional holes must be formed again in the joints 23xe2x80x2 or the body frame 10. Since the distance between the lower end portions of the front pillars 21xe2x80x2 of the cabin frame 20xe2x80x2 is subject to be changed during welding or the like, it is very difficult to form the cabin frame 20xe2x80x2 accurately in desired dimensions. Forming the cabin frame 20xe2x80x2 accurately in desired dimensions increases the manufacturing cost of the utility vehicle. The foregoing problem is true of a case where holes for bolts are formed in the joints 23xe2x80x2 (or the body frame 10) and bolts are attached to the body frame 10 (or the joints 23xe2x80x2).
b) It is difficult to dispose a hood in front of and adjacent to the driver""s compartment under the cabin frame 20xe2x80x2 so as to be opened easily. If the hood is disposed so as to cover a front portion of the body frame 10, when the joints 23xe2x80x2 of the pillars 21xe2x80x2 are placed on and fastened to the body frame 10, the hood cannot be opened unless the cabin frame 20xe2x80x2 is removed from the body frame 10. If the hood is formed between the joints 23xe2x80x2 of the cabin frame 20xe2x80x2 so that it can be opened, the width of the hood is inevitably excessively small. If the cabin frame 20xe2x80x2 is provided with the cross bar 21hxe2x80x2 extended between the lower portions of the front pillars 21xe2x80x2 as shown in FIG. 8A, the cross bar 21hxe2x80x2 restrains the hood from wide opening.
The present invention has been made to solve the foregoing problems a) and b) and it is therefore an object of the present invention to provide a four-wheeled utility vehicle provided with a cabin frame capable of being easily formed and permitting disposing a large hood in front of a driver""s compartment under the cabin frame.
According to the present invention, a four-wheeled utility vehicle has: a body frame; a driver""s seat disposed on the body frame; and a cabin frame having a front portion and surrounding the driver""s seat, the front portion having a pair of lower end portions with vertical joining surfaces, the lower end portions being joined to right and left side surfaces of the body frame via the vertical joining surfaces with bolts having horizontal axes.
Unless otherwise specified, the words xe2x80x9cfrontxe2x80x9d, xe2x80x9crearxe2x80x9d, xe2x80x9crightxe2x80x9d and xe2x80x9cleftxe2x80x9d are used herein to signify position or direction with respect to the direction of forward travel of the fourwheeled utility vehicle. The words xe2x80x9clateralxe2x80x9d, xe2x80x9cback-and-forthxe2x80x9d, xe2x80x9cverticalxe2x80x9d and xe2x80x9chorizontalxe2x80x9d are not used in strict sense and is used to signify being substantially lateral, being substantially back-and-forth, being substantially vertical and being substantially horizontal.
In this four-wheeled utility vehicle, respective portions of the body frame and the cabin frame relating to the connection of the body frame and the cabin frame can be formed in dimensional accuracy lower than that in which the body frame and the cabin frame of the conventional four-wheeled utility vehicle are formed. Since the lower end portions of the front portion of the cabin frame are joined to the right and left side surfaces of the body frame via the vertical joining surfaces of the lower end portions and fastened to the right and left side surfaces of the body frame with the bolts having axes in a horizontal direction, the distance between the vertical joining surfaces of the lower end portions does not need to coincide precisely with the distance been the right and the left side surface of the body frame. When those distances do not coincide with each other, the lower end portions of the front portion of the cabin frame can be warped elastically so that the distance between the vertical joining surfaces coincides with the distance between the right and the left side surfaces of the body frame. If the lower end portions of the front portion of the cabin frame are difficult to warp elastically, the lower end portions of the cabin frame are formed so that the distance between the vertical joining surfaces of the lower end portions is slightly greater than the distance between the right and the left side surfaces of the body frame. In this case, shims may be inserted in gaps between the right and the left side surfaces of the body frame and the corresponding vertical joining surfaces of the lower end portion of the cabin frame when fastening the lower end portions to the body frame with the horizontal bolts. Therefore, the distance between the vertical joining surfaces of the lower end portions of the cabin frame does not need to be highly accurate. The cabin frame that can be formed in a low dimensional accuracy reduces the manufacturing cost of the four-wheeled utility vehicle and facilitates work for attaching the cabin frame to the body frame.
Preferably, the four-wheeled utility vehicle has an openable hood disposed on a front portion of the body frame. Preferably, the front portion of the cabin frame is formed in a shape resembling an inverted letter u and has right and left vertical members and a horizontal member extending between upper ends of the right and the left vertical members, the right and the left vertical members being extended on outer sides of opposite sides of the hood.
The front portion of the cabin frame having the shape resembling the inverted letter U can be laterally and elastically warped so that the distance between the vertical joining surfaces of the lower end portions of the front portion of the cabin frame coincides with the distance between the right and the left side surfaces portions of the body frame.
The four-wheeled utility vehicle can be provided with a large hood of a large area capable of easily be opened under the front portion of the cabin frame on a front portion of the body frame. Since the front portion having the shape of the inverted letter U does not have any member that extends over the hood disposed between the lower end portions of the front portion of the cabin frame, the hood can be wide opened.
The hood ran be formed in a large area because the lower end portions of the front portion of the cabin frame are fastened to the body frame with the vertical joining surfaces thereof in contact with the right and the left side surfaces of the body frame. Even if the vertical joining surfaces are set to be large in order to make the joints strong, a large space for the hood is available between the vertical joining surfaces. If the lower end portions of the cabin frame are fastened to the right and the left side surfaces of a widest portion of the body frame, the hood can be formed in a great width nearly equal to the overall width of the body frame of the four-wheeled utility vehicle. The long distance between the vertical joining surfaces is nothing but a means for forming the hood in a big width and a large area. The hood of a large area capable of being opened wide and disposed in front of the driver""s compartment between the vertical airs of the front portion of the cabin frame facilitates actions to reach into a space under the hood, such as a trunk space for putting things in or taking the same out of the space. A front portion of the four-wheeled utility vehicle can be formed in compact construction, which is advantageous to the four-wheeled utility vehicle.
Preferably, the four-wheeled utility vehicle has a crossbar attached to the body frame and having opposite end portions, and brackets attached to the opposite end portions of the crossbar and having the vertical joining surfaces for joining the lower end portions of the front portion of the cabin frame.
In this four-wheeled utility vehicle, the lower end portions of the front portion of the cabin frame can be firmly held on the opposite ends of the crossbar attached to the body frame because, differing from flat plate-shaped members, the opposite end portions of the cross bar restrain the lower end portions of the front portion of the cabin frame rigidly from movement in all directions. The distance between the lower end portions of the front portion of the cabin frame can be determined principally by the distance between the opposite end portions of the crossbar. The crossbar can be easily processed and can be made at a low manufacturing cost. Since the crossbar supporting the front portion of the cabin frame is disposed in a front portion of the body frame, the crossbar can be used also for supporting parts such as the hood and headlight to be disposed in the front portion of the body frame. Thus, the crossbar is used effectively to prevent increase in the body weight of the four-wheeled utility vehicle.
Preferably, the cabin frame has a rear portion including a lower end portion, the lower end portion being provided with a curved joint having a horizontal joining surface and a vertical joining surface, the curved joint being fastened to the body frame via the horizontal and the vertical joining surfaces with a pair of bolts, one of the bolts having an axis perpendicular to the horizontal joining surface, and another of the bolts having an axis perpendicular to the vertical joining surface.
The connection of the rear portion of the cabin frame to the body frame by the cured joints enhances the rigidity of the rear portion of the cabin frame because the curved joints are fastened to the body frame with the horizontal and the vertical joining surfaces in contact with the surfaces of the body frame. Wherry a joint having a single joining surface is liable to be dislocated when a force acts in a direction parallel the joining surface on the joint or a torque acts in a plane including the joining surface of the joint, a joint having a plurality of joining surfaces not parallel to each other is neither moved nor dislocated by such a force and such a torque.
Since the rear portion of the cabin frame can be rigidly supported on the body frame, the cabin frame is sufficiently rigid even if the crossbar is not disposed under the front portion of the cabin frame in order to get a wide space for the hood. Since the lower end portions of the rear portion of the cabin frame are fastened to the body frame, it is easy to make a load-carrying platform mounted in a rear portion of the body frame to be vertically moved relative to the body frame.